Typically, two-stroke outboard marine engines do not have a separate oiling system. That is, these prior art engines require pre-mixing lubricant and fuel so that the lubricant dissolves in the fuel to lubricate the engine. This requires consistent, accurate measuring and agitation of the mixture. There are many disadvantages to the prior art system of pre-mixing lubricant and fuel. For example, since various two-stroke engines require different mix concentrations, many outboard marine engine owners also own other two-stroke engine equipment, such as various lawn and garden equipment and ATV""s, they may store several different concentrations of oil/fuel mixture. This is not only an aggravation to the owner, but is also problematic if the containers become mixed up and the owner uses the wrong concentration for a particular two-stroke engine. While this is not catastrophic, if run over time with the wrong concentration, a two-stroke engine can wear excessively.
The present invention is for use in a unique lubrication system for two-stroke engines. Such a lubrication system must not only provide lubrication to each cylinder of the engine, it must also provide lubrication to the fuel system to properly lubricate the fuel metering and injection system. Unlike four-stroke engines which are designed to not consume oil but only to re-circulate oil for lubrication, a two-stroke engine, by its nature, consumes oil during use. It has generally been believed that since the oil is consumed by the two-stroke engine, that careful metering of the oil directly to the engine does not need filtering. However, many problems can occur in such a precise metering system. Therefore, it would be advantageous to have a pressurized closed loop oil re-circulation system that periodically diverts oil to the engine. In such an oiling system, it would be advantageous to provide filtering of the oil in the re-circulation system to remove any contaminants that may enter the oil.
The present invention discloses an oil system with a replaceable oil filter that solves the aforementioned problems.
In accordance with one aspect of the invention, an outboard motor includes a two-stroke internal combustion engine and a water propulsion unit in operable association with the two-stroke engine to propel the outboard motor through the water. The outboard motor includes an automatic oil injection system to lubricate the two-stroke engine. The outboard motor also includes an oil system housing having an oil inlet, an oil outlet, and a replaceable oil filter threadedly engaged to the oil system housing to filter lubricant received from the oil inlet.
In accordance with another aspect of the invention, an oil system for a two-stroke engine includes an oil system housing having an oil inlet, an oil outlet, and oil return, and a threaded stud extending from the oil system housing. A replaceable oil filter is threadedly engaged to the threaded stud of the oil system housing to filter lubricant that is recycled through the oiling system and supplied to the two-stroke engine. The oiling system includes a remotely located oil reservoir and an oil pump to pump lubricant to the oil inlet and through the replaceable oil filter.
The invention includes an oil system housing that includes an oil inlet port in communication with a first internal passage, and an oil filter base to replaceably receive an oil filter thereon such that lubricant from the first internal passage is directed into the oil filter and returned to a second internal passage of the oil system housing. The housing further includes an oil return port in communication with a third internal passage of the oil system housing. An oil outlet port is provided in communication with a fourth internal passage of the housing. The housing includes a solenoid chamber to receive a solenoid therein to toggle lubricant flow from the second internal passage to one of the third and fourth passages. When the solenoid is not activated, oil is routed through a closed system that includes the oil filter. When the solenoid is activated, oil is still routed through the filter, but is then diverted to the two-stroke engine.
Various other features, objects and advantages of the present invention will be made apparent from the following detailed description and the drawings.